Method of forming reenforced cementitious slabs



Dec, 30, 1924,

. H. E. MARKS METHOD 0F FORMIG REE'NFORCED CEMENTITIOUS SLABS Filed Feb., 14, 1924 WITNESSE'SS v lNvEN-ron ',Mfamz ahw Patented Dec. 30, 1924..

UNlren oFFicE. f

METHOD OF EORMING B-EENFORGED CEMENTITIOUS SLABS.

Application led February 14, 1924. Serial No. 692,581.

To all whom t may concern.'

Be it known that I, yHnunlrr E. MARKS, a citizen of the United States, and a resident of Glen Osborne, in the county of Allegheny and State of Pennsylvania, have invented a new and useful improvement in Methods of Forming Reenforced Cementitious Slabs, of which the following is a specification.

The invention relates to a method of applying metallic reinforcements to cementitious slabs. its object is to provide for the more accurate positioning of the reinforkcement relative to the surfaces of the sla In fireproof roof and floor construction it is quite common to use what are known as pre-cast cementitious slabs which generally are reenforced by metallic rods, wires or mesh in order to strengthen the same. In making these slabs the metallic reinforcement is placed in the mold, suitably spaced from the bottom of it, and the cementitious material is then poured into the mold and allowed to set. This method is objectionable because it is difficult to hold the reinforcement in proper position in the mold so that in the finished slab it will lie uniformly spaced from the tension side of the slab.

The present invention is designed to overcome this difficulty, and provide a method of forming such slabs that the metallic reinforcement will be uniformly spaced, and at the "best distance ,from the tension side of the slab. This object is secured by providing the cast slab, on its lower or tension side with grooves to receive the metallic reinforcement, which grooves are formed of exactly the right depth and of uniform. depth, to space the reinforcement the proper distance from the tensiony side of the slab.y After being so formed the slab is placed with itsgrooved side on top, the metallic reinforcement is laid into the grooves and down in the bottoms of them, after. which the grooves are lled with cementitious material of the same kind as the body ofthe slab, or of a kind sufficiently similar to it to thoroughly bond with the material of the body of the slab and form a lhomogeneous part thereof. The result is that the reinforcement is thoroughly em* bedded in the slab, is uniformly spaced from the tension side thereof, and can be Speed.. ,from fait tension. .Sniace at sich distance as to get the most effective reinforcement for the slab.

The invention can be applied to any cementitious slab. With certain materials, which form a Very strong bond with the metallic reinforcement, it is necessary to 4provide only longitudinal grooves to receive longitudinal reinforcing members, but with materials such as gypsum, which 1 do not form such astrong bond with the metallic members, it is desirable to provide the slab with transverse grooves or at least transverse portions of grooves, in addition to the longitudinal grooves, and provide the reinforcement with transverse rods or wires,

or at least transverse projections, which lie or extend into the transverse grooves or transverse extensions of the grooves and abut against the walls of said transverse grooves or portions of grooves, and therefore transmit the strains on the longitudi- 'f nal members directly to the body of the cementitious slab.

The invention can be carried out in various ways, such as casting the slabs with flat faces, and then forming grooves, either longitudinal or both longitudinal or transverse, by suitable grinding wheels'o'r other tools; or forming the grooves in the slab in the process of molding it. The longitudinal grooves can be formed `by 4extruding the material through, a suitable die provided i with portions which will form such grooves in a well known manner, and if the slab is to have only longitudinal reinforcing members, this will suffice; and if it is to be reenforced both longitudinally and transversely, the transverse grooves can afterwards be 'formed by a grinding wheel, `or other tool.

Another way is to form the grooves, either longitudinal or both longitudinal and' transverse, by suitable projections in the bottom of the mold. Whichever method is followed, a slab after being formed with the desired grooves, is placed with the groove face on top, and the metallic reinforcement then placed in and embedded in it as hereinbefore described.

Thel reinforcement may be of various forms, but the lpreferred form of such reinforcement, particularly for gypsum slabs will be a welded metallic mesh, comprising longitudinal wires and transverse wires welded at their crossing points, this form or reinforcement @eine preferred beate@ u@ nient applied thereto; Fig. et is a sectionalv View showing such slabs placed in position with the reinforcei'nents at adjacent ends of contiguous 'slabs joined in order to form a continuous reinforcement; and Figs. t5, Tand S are detail viens showing moditications.

As shown in Fig. 1, the mold is provided on 'its bottom with. longitudimil ribs '11 and 't 1ansverse ribs 12, of a width and lieig'ht necessary to form vgrooves of the necessary lWidth 'and height.l rllhe cen'ientitious "material 'is vpoured into this mold in the iisual Way, and mainfestly the slab formed in i't will be provided with longitudinal and transverse Igrooves of a width and depth corresponding to the ribs 11 and 12. After the slab setit is removed from the mold,

turned up-side-doWn, that is, with lits 'io'oved face on top'. `and then the reinforcing mesh is placed in said grooves, with the men'i'bers of it :lying in the bottoni of the ooves,pa.fter which the grooves are filled vvvit'hcei'nfentitious material of the same or similar lind to 'thoroughly and homogeneouslly bond With the body ot the slab. As ovvn lin Figs. 2 and 4- the reinforcement 4comprises 'the longitudinal ivires 13 'and 'transverse Wires 14, ivelded together at the'ircrossilng fpoints and Aforming meshes of the vsame vdimension `as the squares or rectangles `'formed 'by Athe cross grooves in the slab. The. cemen'titious filling material is shown at "15. After this l'has been filled in and thoroughly fset, the reinforcement is thoroughly kembedded inthe slab, and is 'spaced 'uniformly from the tension side of the slab.` `liffanifestly the grooves can be formed 'of Ieinictly'the right depth for any particular slab -so that the reinforcement 'Will "be :spaced the most effective dis yance from the'tension surface ofthe slab.

In'this preferred `form the vmetallic mesh will be so arranged that one ofthe transi 'verse Wires, .such/as 111e, Will lie slightly ber- 'yon'd one vend of thezslab. While at the other end the llongitudinal bWires 13 Will be formed into theliooks orxth'e 'like 16 which y'can be iliade 'to "engage with ,the transverse 'Wire 14? ofthe 'adjacent end of the contiguous isla'bfsuch 'als lshovvn -iny Fig. l, yWhere the slabs are of a length to bridge the space between roof or floor supporting inembers or beams 18, with the reinforcement of adjacent members joined above said beams, as shown, after which the space between said ends ivill be tilled with grouting, thus forming a roof or floor having substantially continuous reinforcement.

Manifestly instead of molding the slabs with the crossed grooves as illustrated, these grooves can be ground or otherwise cut into the .sl/2b by iany suitable grinding` Wheel or tool after the slali is formed; or the longitudinal grooves can betormed by cntmcliug;l through a properly shaped die, and after- Wards the transverse grooves ground or cut the slab. Also instead ot using Welded metallic mesh as shown in Figs. 3 and 4, any other suitable mesh may be employed, such as that illustrated in Fig. 5, Where the longitudinal members or Wires 13a are formed with loops or eyes 19 through which are threaded the transverse Wires or members le", or any other form of mesh in Which the transverse Wires are held against longitudinal movement relative to the longitudinal Wires may be employed.

lt is not necessary to have continuous transverse grooves and continuous transverse reinforcing members. For instance, the transverse grooves may be merely eX- tensi'ons or enlargements 2O or 20?, of the longitudinal grooves 21V or 21a, as shown in 6 and 7, and in this case the longitudinal reinforcing member 22 or 22a may be provided with laterally bent or loop portions as shown in F ig. 6, or 4transverse portions 23' formed by upsetting the lengt tudina'l members. as 'shown in Fig. T, and. which lateral bends, loops or projections extend into the transverse extensions or 20'" ofthe grooves.` and 'thus serve to more thoroughly anchor the longitudinal member in the cementitious body. Another form is shoivn in Fig. 8, Where the longitudinal groove is also 4provided With the transverse extensions 20", and the longitudinal member is in the form of a strip 22h punched with holes at suitable distances apart, through which are inserted pins or the like 25 which project into the lateral. extensions 20h of he groove.

In all of these forms 'the continuoustransN verse Wire. or' the shorter transverse projcctin.f` portions of the longitudinal reinforcing 'members serve to transmit the strains on the longitudinal members directly to the b'ody of the cementitious material, and some 'suoli form is necessary or lat least desirable `ivhen the slabs are formed of gypsum or like material which does not very strongly bond touthe metallic reinforcing members. llith other materials, such as cement@ vvhichgform stronger bond `vvitlu the metallic reinforcement. simple longitudinal grooves with longitudinal reinforcement members either plain or deformed grouted in the longitudinal grooves of the slab, Will su'liice. Various other modifications either in the manner of forming the grooves or in the form and arrangement of the grooves and reinforcement members will readily suggest themselves to persons skilled in the art.

I claim:

l. The method of forming reenforced cementitious slabs which consists in forming a cenientitious slab With grooves in its tension face, inserting reinforcing members in said grooves, and filling the grooves with a cement-itious material that Will bond with the material oi the slab.

2. The method of forming reenforced cementitious slabs Which consists in forming a cast cementitious slab With grooves in its tension face, placing said slab With its grooved face on top, laying a metallic reinforcement in said grooves, and then lilling said grooves With cementitious material of a kind to bond with the material of the slab.

3. The method of forming reenforced cementitious slabs Which consists in forming a cast cementitious slab on its tension side With longitudinal grooves and transverse extensions thereof, placingsaid slab With its grooved face on top, laying in said grooves metallic reinforcement comprising longitudinal members provided With transverse portions extending into vthe transverse extensions of the grooves, and then filling said grooves with cementitious material of a. kind to bond With the material of the slab.

Al. The method of forming reenforced cementitious slabs which consists in forming a cast cementitious slab on its tension side with longitudinal and transverse grooves,

laying in said grooves metallic reinforcing mesh comprising longitudinal and trans- Iverse members, and then filling the said 

